The command takes various subcommands, and different options
depending on the subcommand:
git reflog [show] [log-options] [<ref>]
git reflog expire [--expire=<time>] [--expire-unreachable=<time>]
[--rewrite] [--updateref] [--stale-fix]
[--dry-run | -n] [--verbose] [--all | <refs>...]
git reflog delete [--rewrite] [--updateref]
[--dry-run | -n] [--verbose] ref@{specifier}...
git reflog exists <ref>
Reference logs, or "reflogs", record when the tips of branches and
other references were updated in the local repository. Reflogs are
useful in various Git commands, to specify the old value of a
reference. For example, HEAD@{2} means "where HEAD used to be two
moves ago", master@{one.week.ago} means "where master used to point
to one week ago in this local repository", and so on. See
gitrevisions(7) for more details.
This command manages the information recorded in the reflogs.
The "show" subcommand (which is also the default, in the absence of
any subcommands) shows the log of the reference provided in the
command-line (or HEAD, by default). The reflog covers all recent
actions, and in addition the HEAD reflog records branch switching.
git reflog show is an alias for git log -g --abbrev-commit--pretty=oneline; see git-log(1) for more information.
The "expire" subcommand prunes older reflog entries. Entries older
than expire time, or entries older than expire-unreachable time and
not reachable from the current tip, are removed from the reflog. This
is typically not used directly by end users — instead, see git-gc(1).
The "delete" subcommand deletes single entries from the reflog. Its
argument must be an exact entry (e.g. "git reflog deletemaster@{2}"). This subcommand is also typically not used directly by
end users.
The "exists" subcommand checks whether a ref has a reflog. It exits
with zero status if the reflog exists, and non-zero status if it does
not.

Options for showgit reflog show accepts any of the options accepted by git log.
Options for expire
--all
Process the reflogs of all references.
--expire=<time>
Prune entries older than the specified time. If this option is
not specified, the expiration time is taken from the
configuration setting gc.reflogExpire, which in turn defaults to
90 days. --expire=all prunes entries regardless of their age;
--expire=never turns off pruning of reachable entries (but see
--expire-unreachable).
--expire-unreachable=<time>
Prune entries older than <time> that are not reachable from the
current tip of the branch. If this option is not specified, the
expiration time is taken from the configuration setting
gc.reflogExpireUnreachable, which in turn defaults to 30 days.
--expire-unreachable=all prunes unreachable entries regardless of
their age; --expire-unreachable=never turns off early pruning of
unreachable entries (but see --expire).
--updateref
Update the reference to the value of the top reflog entry (i.e.
<ref>@{0}) if the previous top entry was pruned. (This option is
ignored for symbolic references.)
--rewrite
If a reflog entry’s predecessor is pruned, adjust its "old" SHA-1
to be equal to the "new" SHA-1 field of the entry that now
precedes it.
--stale-fix
Prune any reflog entries that point to "broken commits". A broken
commit is a commit that is not reachable from any of the
reference tips and that refers, directly or indirectly, to a
missing commit, tree, or blob object.
This computation involves traversing all the reachable objects,
i.e. it has the same cost as git prune. It is primarily intended
to fix corruption caused by garbage collecting using older
versions of Git, which didn’t protect objects referred to by
reflogs.
-n, --dry-run
Do not actually prune any entries; just show what would have been
pruned.
--verbose
Print extra information on screen.
Options for deletegit reflog delete accepts options --updateref, --rewrite, -n,
--dry-run, and --verbose, with the same meanings as when they are
used with expire.

This page is part of the git (Git distributed version control system)
project. Information about the project can be found at
⟨http://git-scm.com/⟩. If you have a bug report for this manual page,
see ⟨http://git-scm.com/community⟩. This page was obtained from the
project's upstream Git repository ⟨https://github.com/git/git.git⟩ on
2018-10-29. (At that time, the date of the most recent commit that
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corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
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Git 2.16.1.2.g59c276cf 01/23/2018 GIT-REFLOG(1)